As soon as you stated the tech. said they'd work on 120 volts or 12 volts the bells started ringing.
Are they 120 volt heating pads? Or are they 12 volt heating pads?
If they're 120 volt, are they plugged into something connected to an inverter?
If there's no 120 volt supply they'll never warm up.
Ted 'n' Laurie, plus Jackson (aka Deputy Dog, the Parson Russell Terrier 'fur kid') and, Rylie (who crossed the Rainbow Bridge June 14, 2012).